1. Field of the Invention
The present invention relates to a heads-up display and, in particular, to a heads-up display with an achromatic lens for use in underwater applications.
2. Description of the Related Art
It is known to mount a heads-up display on headgear. For example, U.S. Pat. No. 6,868,360 which issued on Mar. 15, 2005 to Olstad et al., discloses a heads-up display with a waterproof housing having a mounting mechanism which engages a part of a headgear worn by a user to position the heads-up display in a portion of a forward field of view of the user. A magnetic field sensor module is disposed within the housing and provides magnetic field data signals. An optical element having a wide field of view transmits data images representative of the magnetic field data signals to eyes of the user. Compass data may thereby be viewed by the user in low visibility conditions.